1. Field of the Invention
The invention relates to a method and a meter for measuring the quantity of heat abstracted from a circulating flow of liquid by a consumption unit based upon the indirect measurement of the volume flow rate of the liquid, while maintaining a sub heat flow from or to the main heat flow transported by the flow of liquid and measuring the temperature at some points by means of temperature sensors. Such a heat meter may for instance be provided in city-wide heating networks for consumption on small scale by the consumers. In the future, city heating networks will be used in a progressively increasing number of towns and districts in which each house will obtain a connection to a public heating network instead of its own boiler for central heating. From this connection the consumer will obtain the hot water for his home heating system and tap water supply either directly or indirectly by means of a heat exchange.
It has become evident that consumption by individual consumers (and thus total consumption) in such city heating system decreases when the amount of heat consumed by the individual consumer is measured. From the heat quantity meter the consumer will than have an idea of the cost of his heating. For this reason the installation of heat quantity meters for consumption on small scale is considered to be useful.
Existing meters such as, for instance evaporation meters, often have the drawback that they are not accurate enough. With respect to others, such as meters including turbine parts, the initial cost and/or maintenance cost are too high.